Keyboard controller firmware for Atmel AVR and ARM USB families
QMK (Quantum Mechanical Keyboard) is an open source community that maintains QMK Firmware, QMK Flasher, qmk.fm, and these docs. QMK Firmware is a keyboard firmware based on the tmk_keyboard with some useful features for Atmel AVR controllers, and more specifically, the OLKB product line, the ErgoDox EZ keyboard, and the Clueboard product line. It has also been ported to ARM chips using ChibiOS. You can use it to power your own hand-wired or custom keyboard PCB.
Dive into the documentation!